That's a disturbing sign for TV networks heading into the May ratings sweeps, although executives also caution that more people are recording these shows for later viewing.

CBS' "CSI: Crime Scene Investigation," with 14.6 million viewers, was the most popular scripted show.

For the week, CBS had an average of 9.2 million viewers (5.9 rating, 10 share). Fox averaged 8.6 million (5.2, 9) and won among the 18-to-49-year-old audience it concentrates on. ABC had 8.1 million viewers (5.3, 9), NBC 6 million (3.9, 7), the CW 2 million (1.3, 2), My Network TV 1.5 million (1.0, 2) and ION Television 590,000 (0.4, 1).

NBC's "Nightly News" topped the evening newscasts with an average of 8.1 million viewers (5.5, 12). ABC's "World News" was second with 7.4 million (5.1, 11) and the "CBS Evening News" had 5.7 million viewers (4, 8).

A ratings point represents 1,145,000 households, or 1 percent of the nation's estimated 114.5 million TV homes. The share is the percentage of in-use televisions tuned to a given show.

ABC is owned by the Walt Disney Co. CBS is owned by CBS Corp. CW is a joint venture of Warner Bros. Entertainment and CBS Corp. Fox and My Network TV are units of News Corp. NBC and Telemundo are owned by General Electric Co. ION Television is owned by ION Media Networks. TeleFutura is a division of Univision. Azteca America is a wholly owned subsidiary of TV Azteca S.A. de C.V.